fix many internal links

Fixed a number of internal links that need to
go to the GitHub site.

Ran `make www` to perform the above.

2019/burton/README.md

@@ -60,7 +60,7 @@ Compiles cleanly with:
 
 Included is a test script, useful for the corner cases.  As in all good Unix
 programs, it is silent upon success; any output demonstrates an error.  Instead
-of checking correctness, the [check.sh](check.sh) script can simply output the
+of checking correctness, the [check.sh](%%REPO_URL%%/2019/burton/Rcheck.sh) script can simply output the
 results:   (The Makefile contains the spoiler):
 
 ``` <!---sh-->
@@ -92,7 +92,7 @@ All your base belong to us, but the constants seem a bit ... off?
 
 ### Bonus
 
-The script [cow.sh](cow.sh) provides a closer analog, and perhaps a more useful
+The script [cow.sh](%%REPO_URL%%/2019/burton/cow.sh) provides a closer analog, and perhaps a more useful
 interface.
 
 Included is a version without compilation warnings: